There are many answers to this question -- generally though wetter doughs produce loaves with larger air bubbles. Would you like a recipe or do you just want to better understand why your bread is dense?

My question is more regarding the density. I have experimented with numerous different loaf recipes but I always arrive at the same problem: the bread is simply too dense and moist. I am also baking at +6000 ft but I don't think that poses too big of a problem.